Electric control system for supervising relatively movable members



June 12, 1956 K. N. ANDERSSON ELECTRIC CONTROL SYSTEM FOR SUPERVISINGRELATIVELY MOVABLE MEMBERS Filed April 19, 1951 2 Sheets-Sheet l Fmg. E

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ELECTRIC CONTROL SYSTEM ECE suPERvTsTNC RELATIVELY MOVABLE MEMBERS FiledApril 19, 1951 2 Sheets-Sheet 2 Fmg. E

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KARL N I AL AN DERSSON [gy/ETAM? ATTORN EY ELECTRIC CONTROL SYSTEM FORSUPERVIS- ING RELATIVELY MOVABLE MEMBERS Karl Nial Andersson, Grondal,Sweden, assignor to Akgiebolaget Bofors, Bofors, Sweden, a corporationof weden Application April 19, 1951, Serial No. 221,786

Claims priority, application Sweden April 28, 1950 7 claims. (ci. sis-468) This invention relates to electric control systems for supervisingthe movements of two members movable relative to each other and disposedin close proximity. More particularly, the invention relates to electriccontrol systems for supervising the relative movements of elongatedmembers, such as gun barrels, which are so mounted that there is adanger of physical contact or collision between the elongated members.

A control system of the general type, above referred to, is useful inmany iields of application. A particularly useful though not exclusiveeld of application is the supervision of the aiming movements of guns orgun batteries on naval craft. The available space on warships is oftenso limited that the guns must be mounted so closely together that thegun barrels can collide in certain relative positions which is of coursehighly undesirable, or that the discharge from one gun will strike thebarrel of another gun which is equally undesirable. To avoid accidentsof this nature, a member of a gun crew is frequently detailed to watchthe movements of the gunbarrels and to stop the barrel movements by asuitable control device when there is a dangerous approach between thebarrels. Such reliance upon a person is not very satisfactory since itinvolves human reaction, subjective judgment, and the danger that thedetailedl crew member becomes incapacitated during an engagement just ata critical moment. l.

Accordingly, one of the principal objects of the present invention is toprovide a control system which continuously and automatically supervisesthe relative positions of the gun barrels or other elongated members.

Another object of the present invention is to provide a novel andimproved control system which is continuously controlled by themovements of the gun barrels or other elongated members and whichautomatically initiates corrective measures if there is a danger ofcollision or, more generally, a dangerous approach between the gunbarrels.

Other objects, features and advantages will be pointed out hereinafterand set forth in the appended claims forming part of the application.

In the accompanying drawing a now preferred embodiment of the inventionis shown by way of illustration and not by way of limitation.

in the drawing:

Fig. 1 shows diagrammatically two elongated members movably relative toeach other in one plane.

Fig. 2 is a diagram illustrating the range of the relative positionswithin which a collision between the two members is feasible.

Fig. 3 is a typical circuit diagram of an electric control systemaccording to the invention.

Fig. 4 is a graph showing the function of the system according to Fig.3, and

Fig. 5 is a modification of the circuit diagram of Fig. 3.

Referring first to Fig. 1 in detail, this ligure shows two gun barrelsor other elongated members indicated by the two solid lines 1 and 2.These lines (or barrels) should nited States atent be visualized asbeing movable in the plane of the drawing and pivotal about the points Aand B respectively. The curves which the free ends of the lines 1 and 2describe when the barrels are pivoted, are indicated by OA and OB. Theline which connects the intersecting points of the two curves OA and OBis designated by DE. Let it now be assumed that the two lines are in thepositions shown on Fig. 1 in full lines. Then, they will intersect witheach other at the point C on the connecting line DE. Let it be furtherassumed that the two members represented by lines 1 and 2 are forpractical purposes very nearly in the same plane. The angles of thelines relative to the horizontal line AB are designated a and If, now,one of the lines, for instance line 1, remains stationary while theother line 2 is moved within the same plane as the line 1, it will befound that line 2 will collide with line 1 when the line 2 approachesthe line 1 from below and reaches the position indicated by the dashedlines 6. Similarly, line 2 will collide with line 1 when line 2approaches line 1 from above and reaches the position indicated bydashed line 5. It can geometrically be shown that the angles Ai and Az,which lines 5 and 6 form with line 2 when this latter line intersectswith point C, have the same value and are identical with the angles Aonand Aam between line 1 and dashed lines 3 and 4 when line 2 remainsstationary and line 1 is movable in the same plane as line 2. If the twolines 1 and 2 are moving at the same time in the curve as drawnfollowing the variations of angles Aa and a, it will be found that suchcurve assumes the form of a double loop 7.

Fig. 2 shows loop 7, the angles a being entered on the ordinate and theangles on the abscissa. The loop 7 indicates that a collision betweenthe two barrels represented by lines 1 and 2 can occur Within the areadefined by loop 7.

A similar loop is obtained when it is assumed that the barrelsrepresented by lines 1 and 2 are movable in a plane perpendicular to theplane of the drawing instead of in this plane. For high values of theangles a and ,8 in the last mentioned plane, a curve following thevariations of Aa and A in the first mentioned plane would take the formof a small double loop 8. Consequently, a collision between the twobarrels movable in two planes perpendicular relative to each other canbe avoided by means of a device for each plane which is so designed thatit indicates when either of the barrels or lines 1 and 2 reaches anangular position within the area dened by the double loop. However, ithas been found in practice that indicating devices with a sensitivitycharacteristic which represents a double loop, are unnecessarilycomplicated.

According to the present invention, two tangents are drawn parallel toeach other corresponding to the maximal width of a double loop as isshown in Fig. 2 for double loop 7. As will be noted, the paralleltangents are tangential with the two loops of the double loop. lf, now,a device be designed which indicates or otherwise reacts when one of thetwo barrels or lines 1 and 2 reaches an angular position within the areadefined by two tangents, such a device will satisfy all practicalrequirements for avoiding a collision between the two barrels.

A device ofthis type can be simply and reliably manufactured and in Fig.3 is shown a now preferred embodiment of such a device or controlsystem.

The control system according to Fig. 3 comprises two potentiometershaving resistors 12 and i4 respectively, and movable or slidablecontacts 13 and 15 respectively. The two potentiometers are preferablyof identical resistance value. The two resistors 12 and 14 are connectedat both ends to the terminals 16 and 17 of a source of D. C. current;The position of contact 13 is controlled by the elevational position ofthe barrel of a gun 35. The gun is mounted on a platform 36 and elevatedor depressed in a conventional manner by the rotation of a shaft 37extending through the platform and rotated by electric drive means 33.The rotation of shaft 37 is linearly transmitted to slidable contact 13by suitable conventional transmission means shown as a pinion 39 and arack 40. The position of slider contact 15 is similarly controlled bythe elevational position of the barrel of a gun 35 and the mechanism isdesignated by the same reference numerals though primed. lt is assumedthat the barrels of the guns are moved relative to each other in theplane of the drawing.

As is apparent that the voltage which is tapped by contacts 13 and 15from the resistors 12 and 14 respectively, is directly proportional tothe angle between barrels 1 and 2 respectively and the horizontalreference line AB. As a result, the two angles are measured from theright side of the two points A and B or from the left side of these twopoints. if the two potentiometcrs are identical, the same position ofcontacts 13 and 15 will represent the same angle of the barrels of guns35 and 35. It will be obvious from the previous explanation that the twopotcntiometers are in eiect angle detecting means and that it' is alsoquite possible and in some instances preferable, to use other types ofdetecting means such as variable transformers.

Contact 13 is connected to a point 21 which forms the junction pointbetween the two inner ends of two resistors 18 and 19 connected inseries. The two outer ends of the resistors are connected to a D. Cv.source 2t) and also to one side of two rectifiers 22 and 23 connected inopposition in series.

It will be apparent that the rectiliers can be replaced by polarizedrelays as is shown in Fig. 5 more fully explained hereinafter.

The junction point 24 between the two rectiiiers 22 and 23 is connectedto slidable contact 15. This connection includes a coil 25 of apolarized relay which has two xed contacts 27 and controls a movablecontact 26 normally biased into a neutral position. The contacts 27 areconnected to a terminal 29, Contact 26 to a terminal 28. Terminals 23and 29 are connected through a source of power 41 to the coil of a relay42 the armature 43 of which controls switch contacts 44 and 44respectively. These switch contacts are included in the circuitconnections of drive means 35 and 33 respectively with a common powerline 45.

The control system according to Fig. 3 further includes indicating meansfor indicating the angular positions of the gun barrels. Theseindicating means which may be a conventional design are not shown indetail. but they should be visualized as being connected to terminals 33and 34. For the purpose of controlling the indicating means a secondpolarized relay is provided which includes a coil 30 connected toslidable contacts 13 and 15. Coil 30 controls a movable contact 32 whichcoacts with a xed contact 31 and is normally biased into a disengagedposition.

The` operation of the control system, as hereinbeforc described, is asfollows: Let it be rst assumed that the two slidable contacts 13 and 15are in the same position on the respective resistors 12 and 14. Thismeans that the two contacts indicate the salme angle of the barrels ofguns 35 and 35 and that, hence, these barrels are parallel one with theother and point into the same direction. As a result of these equalpositions of the contacts, no current will ow between the two contactsas they tap the same voltage. Let it now be assumed that the angularposition of the barrel of gun 35 is slightly changed and that as aresult contact 13 is moved a little toward the right. Then, there willbe a voltage difference between the two contacts. However, no currentcan tlow between the two contacts as yet due to the voltage drop overresistor 18 and also due to the blocking effect of rectifier. P'

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23. When, now, the movement of the barrel of gun 35 is continued andcontact 13 is further moved to the right, current will begin to tlowbetween the two contacts as soon as the voltage difference between thetwo contacts exceeds the voltage drop.

Similarly, if contact 15 had been moved to the right, no current betweenthe two contacts can How duc to the voltage drop over resistor 19 andthe blocking effect of rectifier' 22 until the voltage diiferenceexceeds the voltage drop over resistor 19.

,lt will also be apparent that when both slidable contacts are moved,the flow of current will begin when the two contacts reach a relativeposition in which the voltage dierence between them exceeds the voltagedrop over resistors 18 and 19 respectively.

The resistance values of resistors 1S and 19 arc prei-V erably soselected so that the voltage drops across the resistors are equal. As aresult, the tlow of current will begin and the relay coil 25 will beenergized when the absolute value of the difference between the an gulai' positions of the two barrels exceeds a certain value which isdetermined by the voltage drops across thc resistors 15) and 19.

As previously described, contacts 26 and 27 which are controlled by coil25, control the operating mechanisms of the gun barrels through relay42, switch contacts 44, 44 and drive means 33, 38. These operatingmechanisms can be so designed in a manner well understood in the artthat as soon as the flow of current begins and the relay coil 25 isenergized, the moving mechanisms impart to the barrels such movementsthat the barrels are moved into a parallel position or into any otherposition in which a collision between the barrels is avoided. It is alsopossible to arrange the moving mechanisms so that a further movement ofone barrel is stopped and that the other barrel is so moved that it isturned away from the first barrel. Of course, various other arrangementsof the moving mechanisms are possible. lt is believed that it is notessential to the understanding of the invention to explore all possiblearrangements. lt sufces to say that the arrangement should be so thatthe moving mechanisms prevent a dangerous approach of the two barrelswhen relay coil 25 is energized.

The graph according to Fig. 4 shows the current tlow over the controlsystem as a function of the difference in the angular positions of thegun barrels.

The width of the control zone in Fig. l can be varied by varying thevoltage drops across the resistors 18 and 19. Generally, the zone isgiven the relative width as shown in Fig. 1. However, if the elongatedmembers are gun barrels it is preferable to make the zone wider toprevent also that a discharge from one gun barrel may strike or comeclose to the other gun barrel.

The second polarized relay which controls the indicating means connectedto the terminals 33 and 34, is controlled by the direction of the flowof current between the slidable contacts 13 and 15.

The circuit diagram of Fig. 5 is generally evident from the previousdescription. As is apparent rccticrs 22 and 23 of Fig. 3 are replaced bycoils 22 and 23 of two polarized relays. One or the other of the relaycoiis will actuate the respective switch contacts 26' and 29', dependentupon the direction of flow of current through the control circuit. Inother words, the polarized relays of Fig. 5 perform the function of thepolarized relay 25 of Fig. 3.

For the purpose of supervising the movements of the gun barrels or otherelongated members in the plane vertically to the drawing, that is, theazimuth movements of the gun barrels, a second control system identicalwith the described one is provided, the slidable contacts of which arecontrolled by the azimuth turning of the gun barrels.

Whilethe invention has been described in detail with respect to acertain now preferred example and embodiment of the invention it will beunderstood by those skilled in the art after understanding theinvention, that various changes and modiiications may be made withoutdeparting from the spirit and scope of the invention, and it isintended, therefore, to cover all such changes and modifications in theappended claims.

What is claimed as new and desired to be secured by Letters Patent is:

1. In an installation of the cl-ass comprising two elongated memberseach pivotally mounted for angular movements relative to a commonreference plane and to each other, the said members being disposed in aspacial relationship in which the two members are capable of approachingeach other beyond a predetermined limit of approach, the combinationwith a safety control system comprising two sources of a variablepotential, each of said sources being connected with one of said membersfor control of the respective potential by the angular position of therespective member relative to the said reference plane, control circuitmeans including two series connected sources of a liXed potential andtwo unidirectionally conducting electric means series connected inopposition, one of said sources of a variable potential being connectedto the connection point between the sources of a iiXed potential of thecontrol circuit means and the other of said sources of a variablepotential being connected to a connection point between the twouni-directionally conducting electric means, the respective one of thesaid electric means becoming conductive in response to a tlow ofpotential between the two variable sources of potential and through saidcontrol circuit means in one or the other direction, the direction ofthe said flow being controlled by the relative angular position of thetwo members, and electric controlled circuit means for controlling therelative movements of said members and controlled by the conducting oneof the two uni-directionally conducting electric means.

2. In an installation of the class comprising two elongated members eachpivotally mounted for angular movements relative to a common referenceplane and to each other and a moving mechanism for moving the twomembers relative to each other, the said members being disposed in aspacial relationship in which the two members are capable of approachingeach other beyond a predetermined limit of approach, the combinationwith a safety control system comprising two sources of a variablepotential, each of said sources being connected with one of said membersfor control of the respective potential by the angular position of therespective member relative to the said reference plane, control circuitmeans including two series connected sources of a fixed potential andtwo uni-directionally conducting electric means series connected inopposition, one of said sources of a variable potential being connectedto the connection point between the sources of a fixed potential of thecontrol circuit means and the other of said sources of a variablepotential being connected to a connection point between the twouni-directionally conducting electric means, the respective one of thesaid electric means becoming conductive in response to a ow of potentialbetween the two variable sources of potential and through said controlcircuit means in one or the other direction, the direction of the saidow being controlled by the relative angular position of the two members,the said uni-directionally conducting electric means being arranged tobecome conductive in response to a difference in potential above a 6predetermined minimum value, and electric controlled circuit means forcontrolling the relative movements of said members and controlled by theconducting one of the two uni-directionally conducting electric means.

3. A control system as delined in claim 2, wherein the said two sourcesof a variable potential each comprise potentiometer means connected incircuit with a source of current, the variable contacts of the saidpotentiometer means being operatively coupled with the said members formovement of the same and electrically connected to the connection pointbetween the two sources of a fixed potential and the twouni-directionally conducting means respectively.

4. A control system as dened in claim 2, wherein the said two sources ofa Xed potential comprise two resistance means connected in series with asource of current.

5. A control system as dened in claim 2, wherein the said twouni-directionally conducting electric means comprise two rectifyingmeans connected in series opposition, and wherein the said electriccontrol means comprise polarized relay means, the said relay meansincluding coil means included in the circuit connection between theconnection point of the two rectifying means and the respective sourceof a variable potential and two switch means each connected in circuitwith said controlled circuit means for controlling the relative positionof said members, the said coil means causing actuation of one or theother of said switch means for control of the said controlled circuitmeans when one or the other of the rectifying means becomes conductive.

6. A control system as deiined in claim 5, in combination withadditional polarized relay means connected between the two sources of avariable potential and responsive to the direction of a ilow ofpotential between the said two sources, the said additional relay meansbeing connected in circuit with said controlled circuit means forcontrolling the relative position of said members.

7. A control system as defined in claim 2, wherein each of the saidunidirectionally conducting electric means comprises a polarized relaymeans including a coil means and a switch means controlled by theenergization of the coil means, the said relay coil means beingconnected in series with each other and the said two sources of a xedpotential, the said two switch means being connected in circuit withsaid controlled circuit means for control of the latter for the puropseaforesaid by actuation of either of the switch means as controlled bythe direction of iiow of a potential through the control circuit means.

References Cited in the le of this patent UNITED STATES PATENTS 625,647Crehore et al. May 23, 1899 1,299,509 Rey Apr. 8, 1919 2,373,208Trucksess Apr. 10, 1945 2,439,198 Bedford Apr. 6, 1948 2,498,103Nojciechowski Feb. 21, 1950 2,525,038 Kutzler Oct. 10, 1950 2,583,058Libman Ian. 22, 1952 OTHER REFERENCES Electrical Engineering, November1948, p. 1059.

